Conventional light sources have been limited in application to flexible devices due to their physical and mechanical properties such as hard and inflexible materials. Recently, a deformable and stretchable light source has attracted a lot of attention in order to provide flexible electronic devices.
Currently, studies to provide stretchiness to light emitting devices are being conducted. In a conventional light emitting device having stretchiness, a transparent electrode material is embedded in an elastic polymer material to provide elasticity to an electrode which has a minimized decrease in electrical properties during tensile strain or a light emitting material is dispersed in an elastic polymer material with stretchiness to provide stretchiness.
However, the conventional flexible light emitting device has a low elongation percentage of about 100% and requires a high driving voltage for light emission and decreases in electrical properties and luminous intensity at the same time as being elongated.
In this regard, Korean Patent Laid-open Publication No. 10-2012-0017779 (entitled “Flexible organic light-emitting diodes and manufacturing method thereof”) discloses a method of manufacturing flexible organic light-emitting diodes by performing electric field annealing to a FOLED including a polymer anode layer formed on a flexible substrate, a light emitting layer formed on the polymer anode layer, an electron injection layer formed on the light emitting layer, and a cathode layer formed on the electron injection layer.